Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > Surface chemistry_XII > Flashcards

Surface chemistry_XII Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

Adsorption

A

Surface phenomenon.

Its the increase in concentration (aggregation) of any molecule at the surface rather than at bulk.

May occur above a ‘solid’ or ‘liquid’ surface. **(not gaseous surface =common sense hai gas pe koi particle kese ruk payega).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Adsorbent

A

Solid or liquid surface ON which molecular species are adsorbed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Adsorbate

A

Molecular species which IS adsorbed on the surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Absorption is a _____ phenomenon whereas adsorption is ____ phenomenon.

A 
A’b’sorption = ‘b’ulk phenomenon 
Adsorption = surface phenomenon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

CaCl2 ______water vapours ; silica gel _____ water vapours.

Absorbs/adsorbs

A

CaCl2 absorbs water vapours ; silica gel adsorbs water vapours.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Desorption

A

When molecular species are removed from the surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Occlusion

A

Adsorption of gas on solid surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Adsorption is _______[exo/endo thermic] process.

A

Exothermic (heat is released).

Δ H -ve
Δ S -ve (entropy of gas molecules decreases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

For the process to be spontaneous, magnitude of;
Δ H
Δ G

A

Δ H > T ΔS i.e ΔG<0 (-ve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

On increasing temperature, magnitude of T ΔS _____ & ΔG _____.

A

Magnitude of T ΔS increases whereas |ΔG| decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Select correct statements regarding Physical adsorption (physisorption):

a) not specific.
b) reversible.
c) results in multilayer adsorption
d) not.
c) all of these.

A

All of these.

It decreases with increase in temperature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Physisorption ______ with increase in temperature.

A

Decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Chemisorption _______ with increase in temperature.

A

Increases with increase in surface area.

First increase , attains maximum & then decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In Freundlich isotherm, value of 1/n & n ranges from?

A

1/n = 0.1 - 0.5

=> n = 2 - 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

According to ______theory all adsorption sites are equivalent.

A

Langmuir isotherm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Greater the surafce area _____ is the rate if adsorption.

A

Greater.

Porous surfaces will show more rate of adsorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

KClO3 ———>KCl +3/2 O2

Write the catalyst involved?

A

MnO2

Temp.= 400-600K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What’s promotor?

A

Increases activity of catalyst.

Eg,s MO & K2O are used in Haber’s process as promoter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What’s poison?

A

Decreases activity of catalyst.

Egs., As, Co, Quinoline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

SO2 + ½ O2 ———>SO3

Is an example of ?

A

Homogeneous catalysis, if catalyst used is NO (g)

Heterogeneous catalysis, if catalyst used in V2O5. [Contact process]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

SO2 + ½ O2 ———>SO3

Is homogeneous catalysis if catalyst is

A

NO (g)

*reaction/process is called ‘lead chamber process’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

SO2 + ½ O2 ———>SO3

Is heterogeneous catalysis if catalyst used is

A

V2O5

*reaction/process is called CONTACT PROCESS .

This is one of 3 MOST IMPORTANT RXNS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

CH3COOC2H5 + H2O ———>CH3COOH + C2H5OH
Ester. Water. C.acid. Alcohol
whats the catalyst used for this homogeneous catalysis rxn.

A

H+ (aq.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

C12H22O11(sucrose/sugar) + H2O ———> C6H12O6 (Glucose) + C6H12O6(fructose)
Catalyst used??

A

H+ (aq.)

25
Q

Examples of heterogeneous catalysis?

A

the 3 most important rxns.

Contact process: SO2 + ½ O2 ———>SO3 (V2O5 as catalyst)
Haber’s process: N2 + 3H2 ———>2NH3 (Fe as catalyst; Mo as promoter)
Ostwald’s process: NH3 + O2 ———>NO + H2O (Pt as catalyst)

26
Q

Na2SO3 ———> Na2SO4

In presence of Na2ArO3 (sod. Arsenate) & O2

A

Is an example of induced catalysis

27
Q

Example of auto-catalysis?

A

MnO4 + C2O4 + H+ ———> Mn+2 + CO2 + H2O

Here, Mn+2 produced is used as catalyst for the rxn.

28
Q

According to modern adsorption, what’s the mechanism of catalysis?

A

Diffusion>adsorption>reaction>desorption>diffusion.

29
Q

Zeolites/selective shape catalyst?

A

Hydrated sodium aluminium silicates. (3D str.)

30
Q

ZSM-5 a zeolite, acts as catalyst for

A

Alcohols(R-OH) into gasoline(R-H) i.e dehydrates

31
Q

1) CO + H2 ———>CH4 + H2O
2) CO + H2 ———>CH3OH
3) CO + H2 ———>HCHO
Write catalysts for each of these?

A

1) CO + H2 ———>CH4 + H2O ; Ni
2) CO + H2 ———>CH3OH ;CuO/ZnO-CH2O3
3) CO + H2 ———>HCHO ; Heat only

32
Q

Sugar(C6H22O11) +H2O ———> Glucose + fructose

Name the enzyme catalysis?

A

Invertase.

33
Q

C6H12O6 ———>C2H5OH + CO2

A

Zymase.

34
Q

(C6H12O6)n———> C6H22O11 (maltose)

A

Diastase.

35
Q

C12H22O11 + h2o ———> C6H12O6 (glucose)

A

Maltose.

36
Q

NH2CONH2 (Urea) + H2O ———>NH3 + CO2

A

Urease.

37
Q

Proteins ———>peptides ———>aminoacids

A

Proteins ———> peptides. ; Pepsin

Peptides ———> amino acids. ;Trypsin

38
Q

Triglycerides ———>glycerol + fatty acids

A

Lipase

39
Q

Activators

A

Metal ions like Na+ , Mn+2, CO+2

40
Q

Co-enzymes are ?

A

Substances which increases activity of enzymes.

41
Q

Inhibitors destroy the catalytic activity of enzymes.
Poisons are substances which slows down activity of enzymes.
- both correct
-both incorrect
- 1st correct
- 2nd correct

A

Both are correct.

42
Q

Mention particle size in each of these:
A) true solution
B) colloidal solution
C) suspension

A

A) true solution = less than 10 A°
B) colloidal solution = 10-10^4 A°
C) suspension = greater 10^4 A°

43
Q

Adsorption isostere are

A

Plot at constant x/m b/w pressure and temperature.

44
Q 
For adsorption generally ΔH, ΔG, ΔS are:
\+,-,+
\+,-,-
-,+,-
-,-,-,
A

ΔH -ve
ΔG -ve
ΔS -ve

45
Q

In freundlich isotherm, slope of plot of log x/m vs log p gives

A

Value of 1/n

46
Q

According to langmuir isotherm, amount of gas adsorbed at very low pressure is

A

Directly proportional to pressure.

47
Q

According to langmuir isotherm, amount of gas adsorbed at high pressure is

A

Independent of pressure as at high pressure x/m is constant.

48
Q

For langmuir isotherm; Slope of straight line of plot of P/(x/m) vs P graph gives/is

A

b/a

Where b and a are langmuir parameters .
Also, the intercept if this graph = 1/a

49
Q

Ultra filter paper used in ultrafiltration is prepared by

A

Soaking a filter paper in a colloidal soln. (4% soln. Of nitro cellulose in a mixture of alcohol and ether) hardening by formaldehyde and then dried.

50
Q

Tyndall effect is not shown by true solutions.

T/F

A

True

51
Q

Tyndall effect is due to

A

Scattering of light by colloidal particles (dispersion phase)

52
Q

FeCl3 added in excess hot water forms a positively charged sol of hydrated ferric oxide.
(T/F)

A

True.

And a negatively charged sol when FeCl3 is added in NaOH due to adsorption of OH- ions

53
Q

Electrokinetic potential or zeta potential is?

A

Difference in potential b/w electrical double layer of opposite charge (called Helmontz electrical double layer) is c/d zeta potential

54
Q

Coagulating power is inversely proportional to coagulation value.
(T/F)

A

True

55
Q

Colloidal antimony is used in curing

A

Kalazaar

56
Q

_______ sol is used as an eye lotion.

A

Argyrol in silver sol

57
Q

Colloidal gold is used for

A

Intramuscular injection

58
Q

_______ is an emulsion used for stomach disorder.

A

Milk of magnesia.

59
Q

4 methods to coagulate lyophobic colloids?

A

Electrophoresis
By mixing 2 opposite charged sols
By boiling
By addition of electrolytes

Chemistry (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions